Lubricating compositions



United States Patent 2,916,449 LUBRICATING COMPOSITIONS Ernest R. Vierk,Lansing, 111., and Theodore J. Karr,

East Chicago, Ind., assig'n'o'rs 'to Sinclair Refining Company, NewYork, N.Y., 'a corporation of Maine No Drawing. Application July 22,1957Serial No. 673,110

12 Claims. (Cl. 252 -32.?)

This invention relates to lubricants and is particularly concerned witha new lubricant composition which is especially advantageous as a papermachine circulating system oil.

The dryer end of modern Fourdrinier paper machines contains, on theaverage, 50 to 100 hollow cast iron cylinders which are heatedinternally by steam. The presence of this steam and the inevitable pulpand paper bits presents an important lubrication problem in this field.The natural construction of these machines renders the parts which mustbe lubricated and contacted by lubricating oil inaccessible.Consequently, it has become conventional to design an automaticlubrication system into the machine. The automatic lubrication system,known as the oil circulating system, normally comprises an oilreservoir, lubrication lines to the bearings, side gears, etc., a meansfor settling, filtering and purifying the oil. The oil employed hasthree main functions, these being lubrication, cooling and flushing.

Conditions obtaining in the oil circulating systems of these papermachines necessitate the use of oils which are characterized byessentially inconsistent properties. For example, the oil must havesufficient emulsification properties to insure the pickup of anymoisture in the system, particularly in the anti-friction bearings, andstill be characterized by sufficient demulsification property to releasethe water content in the time the oil normally remains in the reservoir,i.e., normally about an hour or so. Such oils must have high loadcarrying capacity at high temperature and simultaneously be capable ofacting as a bearing and gear coolant. The use of higher speeds in papermachines requires higher temperatures to effect drying in the shortertime available. Higher speeds and temperatures aggravate the lubricationproblem as does the fact that shutdowns for bearing failures and thelike result in losses of the order of thousands of dollars per hour.

We have now discovered a novel lubricating composition especially usefulas a circulating system oil for paper machines. By our invention alubricant is disclosed which provides rust protection, is oxidationresistant at high temperatures, is characterized by improved loadcarrying capacity and improved film strength, and is especiallydistinguished by a unique balance of emulsification and demulsificationproperties. This aspect relating to emulsification and demulsificationprop- 'erties chaiacterizes the lubricant composition with the propertyof emulsifying moisture which normally enters the lubricating lines, thebearing and gearing housings, etc. and still permits ordinarydemulsification of the 2,916,449 Patented Dec. 8, 1959 ice Weightpercent Lube Oil 7510-99 Sulfonate 0.3 to 20 Metal dithiophosphate 0.5to 1.8 Alkyl phenyl phosphate 0.3 to 3.5

We have found it advantageous to include an anti-foam agent in ourcomposition, such as a silicone polymer having a viscosity of l00centistokes at 25 C. and known commercially as DCF (Dow Corning FluidNo. 200-100). The anti-foam agent, when employed, is present in amountsof about 0.0005 to 0.0015 weight percent. The preferred products of ourinvention have the following composition: about 93 to 98.5 percent oil,about 0.5 to 5 percent calcium or barium sulfonate, about 0.6 to 1.2percent metal dithiophosphatc, and about 0.5 to 1.0 percent alkylphenylphosphate.

Each of the components employed in our new cornposition is commerciallyavailable. For example, the lubricating oil employed is advantageously amineral lubricating oil, and in general, can be a solvent refined ordistilled neutral oil, solvent refined bright stock or the like orblends of two or more lubricating oil fractions, and can be derived fromMid -Continent, naphthenic 01' Pennsylvania crudes. An advantageousblend consists of about 24 volume percent of a solvent refinedMid-Continent neutral oil having a viscosity of about 200 SUS at 100 F.and about 76 volume percent of a solvent-refined Mid-Continent brightstock having a viscosity of about 120 SUS at 210? F.; this blend has aviscosity of about 975 SUS at 100 F. The amount and type of oil includedis chosen so that the resulting composition has a viscosity of about 650to 1000 SUS at 100? F., and preferably about 650 to 850 SUS at 100 F.Also, the base lubricating oil is chosen so that the compositions have aviscosity index of at least about and preferably at least about in orderto enhance their demulsification properties.

The calcium or barium mahogany petroleum sulfonates employed in ourcomposition are those obtained by neutralizing the oil-soluble petroleum'sulfonic acids obtained as in conventional treatment of liquidpetroleum oil fractions with oleum to produce medicinal and other highlyrefined oils. More particularly, a gas oil or lube oil fraction iscontacted with oleum, sulfur trioxide or other sulfonating agent, theresulting sludge layer is separated and the mahogany sulfonic acidscontained in the oil layer are neutralized with lime or barium oxide, asappropriate, in water. These sulfonates can be produced by variousmethods to provide normal or basic sulfonates.' When the sulfonate isbasic we prefer that at least about 1.1 times the amount of calcium orat least about 1.5 times the amount of barium, as appropriate, bepresent than is needed to provide a neutral or normal sulfonate. Acarbonated sulfonate which can be employed can be obtained by contactingthe mahogany sulfonate, e.g. a basic barium sulfonate, with carbondioxide until the strong basicity of the sulfonate to phenolphthalein isreduced and a final pH of about 7 to 8.5 is obtained. This can becarried out. for example, by introducing the sulfonate to the top of apacked column and then feeding carbon dioxide to the bottom of thetower. The carbonated mahogany sulfonate is then recovered and vacuumdried to obtain the final product. As an example, a typical carbonatedbasic barium sulfonate prepared from an oleum-treated West Texas gas oilfraction analyzed 2.86 percent barium and had a base No. to pH 4 of11.3. The sulfonate usually contains unreacted lubricating oil which canbe added to our compositions as part of the base oil The metaldithiophosphate oxidation inhibitors, such as zinc dithiophosphate, andthe alkyl phenyl phosphate components of the new compositions are alsowell known. In general'the metal dithiophosphates to be employed arediesters and contain about 3 to 18 carbon atoms in the organic radicalsand preferably 3 to 10 carbon atoms. Metal dithiophosphates can be madeby any known procedure, for example by contacting the reaction productof a suitable alcohol and phosphorus pentasulfide with a metal oxide,e.g. zinc oxide. Alkyl phenyl phosphates employed contain one or twoalkyl groups per molecule with each alkyl chain having about 3 to 18carbon atoms, and preferably 3 to 10 carbon atoms; in the dialkyl forms,the alkyl radicals need not be the same. Mixtures containing monoalkyland dialkyl phenyl phosphates can also be employed. Alkyl phenylphosphate, dialkyl phenyl phosphates or mixtures of monoalkyl anddialkyl phenyl phosphates are prepared typically by reacting phosphoruspentaoxide with a commercial grade phenol, e.g. diamyl phenol, at anelevated temperature on the order of 275 F. Typical examples ofsatisfactory phosphates include monoand dibutyl phenyl phosphate,dipropyl phenyl phosphate, hexyl phenyl phosphate, dihexyl phenylphosphate, pentyl hexyl phenyl phosphate, etc. The alkyl phenylphosphate and metal dithiophosphate can also be obtained in solution inlubricating oil which can be added as part of the base oil of ourcompositions.

Compositions of the present invention can be made without observingspecial conditions of temperature, pressure, order of mixing or thelike. For example, each of the components may be added to the oil baseseparately, or the zinc dithiophosphate, alkyl phenyl phosphate andsulfonate can be premixed in the desired proportions and then added tothe oil base. As a practical matter we prefer to heat the resultingmixture to about 100 F. to facilitate rapid solution and stir the massto insure a homogeneous mixture.

The invention will be described further with reference to the followingspecific examples:

EXAMPLE I A composition was made by adding 1.4 pounds of zincdithiophosphate, obtained by reacting zinc oxide with the reactionproduct of P 8 and a mixture of hexanol and heptanol, 1.0 pound ofdiamyl phenyl phosphate and pounds of barium mahogany petroleumsulfonates to 82.6 pounds of a mineral oil blend composed of 24 volumepercent of a solvent-refined Mid-Continent neutral oil having aviscosity of 200 SUS at 100 F. and 76 volume percent of a solventrefined Mid-Continent bright stock having a viscosity of 120 SUS at 210F. The resulting compositions had the following characteristics:

Table I Gravity 26.9 Flash, F. 445 Fire, F. 505 Viscosity at F. 780Viscosity at F. 332 Viscosity at 210 F. 77.8 Viscosity index 96.0 Pour,"F 10 Color 7 Carbon residue, percent 1.41 Sulfated ash, percent 1.05Acid No. D-974 1.18 Acid No., D-664 1.41 Base No., D-664 1.30 Barium,percent 0.511 Phosphorus, percent 0.118 Zinc, percent 0.082 Sulfur,percent 0.40 Foam, ASTM D-892:

Sequence I 95-0-36" Sequence II -0-3'40 Sequence III 600-236" Thecomposition of this example was subjected to various tests to determineits usefulness as a paper machine circulating system oil. For purposesof comparison, tests also were conducted on four commercially availablepaper machine circulating system oils. The data obtained are:

Compo- Commercial Oils sition Of Example A B C D Steam Emulsion Test:

Percent 011 recovered in 3 m 100 Percent Oil recovered in 20 min 85-9520-65 5-15 0-15 Modified Navy Emulsion Test:

Percent 011 recovered in min. 100 Percent 011 recovered in 60 m 85 10 1580 Humidity Cabinet Pass Pass Fail Fail Fail Hours 200 200 24 72 96Timken Load Carrying Ca pacity:

Lbs. Pass 25 17 16 16 20 Lbs. Fail 28 20 19 19 23 The steam emulsiontest gave somewhat erratic results on our composition, and on commercialoils A, B and D. The Navy emulsion test, however, gave reasonablyreproducible results for all the oils tested. The decided superiority ofour oil is clearly shown in this test. The results of the humiditycabinet and load carrying capacity tests are further indicative of thesuperior properties of our compositions.

The following tables, Table II and Table HI, include additional datashowing the advantageous properties of our compositions.

The base oil of the above compositions was comprised of a blend asdefined in Example I and small amounts of lubricating oil employed asdiluent for the additives. The zinc dithiophosphate and diamyl phenylphosphate were added as approximately 60 percent concentrates while thesulfonate was about 13 percent active.

Table III Weight Percent Composition Base 0" Balance Balance BalanceBalance Basic Barium Mahogany sulfonete Oil Concentrate. About ActiveIngredient (Base No. 14.3, Wt. Percent Ba. 3.54) 15. 0 Carbonated BasicBarium Mahogany Sulfonate Oil Concentrate, About 13% Active Ingredieut(pH 7.1, Wt. Percent Ba 4.54) 1 6 Basic Calcium Mahogany Sulfonate OilConcentrate About 10% Active Ingredient (Base NO. 4.4, Wt. Percent Ga0.61) 25. 8 Zinc Dithiophosphate (of Example I) Oil Concentrate About60% Active Ingredient 1.4 Zinc Dithiophosphate (of Example I) OilConcentrate About 47% Active Ingredient; 8 1 3 8 Diamyi Phenyl PhosphateOil Concentrate About 60% Active Ingredient 1- 0 0 -0 DOF 0.001 0.0010.001 Viscosity Index 97. 7 96. 4 101. 8 7is%osity, SUS at 100 F 6 4 2650 es s:

Modified Navy Emulsion Test at 180 F.-

Minutes for 100% Recovery of Oil 2 4 Percent Oil Recovered in 60Minutes-.. 85

The base oil of composition (a) was comprised of a blend as defined inExample I, and in addition the small amounts of lubricating oil employedas diluent for the additives were also in the composition. The base oilof compositions (b), (c) and (d) was comprised of a min eral oil blendcomposed of 29 volume percent of a solvent-refined Mid-Continent neutraloil having a viscosity of 200 SUS at 100 F. and 71 volume percent of asolvent-refined Mid-Continent bright stock having a viscosity of 120 SUSat 210 F. The compositions also contained the lubricating oil present inthe additives. A comparison of the data presented on composition (a) andthe data presented for the composition prepared in Example I on page 7,lines 24 to 26, for example, also illustrate the necessity of employingthe alkyl phenyl phosphate along with the sulfonate to obtain adequateemulsifying and demulsifying action since upon subjection of composition(a), which does not contain diamyl phenyl phosphate, to the modifiedNavy emulsion test at 180 F., sixty minutes were required to recover 85percent of the oil whereas upon subjection of the composition preparedin Example I, which does contain diamyl phenyl phosphate, only nineteenminutes were required to recover all of the oil.

This application is a continuation-in-part of application Serial Nos.473,463, filed December 6, 1954, and 573,085, filed March 22, 1956, bothnow abandoned.

We claim:

1. A lubricant composition consisting essentially of about 75 to 99weight percent of a mineral lubricating oil, about 0.3 to 5 Weightpercent of a sulfonate selected from the group consisting of calciummahogany petroleum sulfonates and barium mahogany petroleum sulfonates,about 0.5 to 1.8 weight percent of zinc dialkyl dithiophosphatecontaining about 3 to 18 carbon atoms in the organic radicals and about0.3 to 3.5 weight percent of alkyl phenyl phosphate in which each alkylchain present contains about 3 to 18 carbon atoms, said compositionhaving a viscosity index of at least about 85 and a viscosity (SUS) at100 F. of about 650 to 1000.

2. The composition of claim 1 in which the zinc dialkyl dithiophosphatecontaining about 3 to 10 carbon atoms in the organic radicals and, thealkyl phenyl phosphate zinc dialkyl dithiophosphate containing about 3to 18 car bon atoms in the organic radicals and about 0.3 to 3.5 weightpercent of alkyl phenyl phosphate in which each alkyl chain presentcontains about 3 to 18 carbon atoms, said composition having a viscosityindex of at least about 85 and a viscosity (SUS) at 100 F. of about 650to 1000.

4. The composition of claim 3 wherein the sulfonate is a carbonatedbasic sulfonate.

5. The composition of claim 4 wherein the alkyl phenyl phosphate isdiamyl phenyl phosphate.

6. The composition of claim 4 wherein the composition has a viscosityindex of at least about 95.

7. The composition of claim 4 wherein the alkyl phenyl phosphate isdiamyl phenyl phosphate and the composition has a viscosity index of atleast about 95.

8. A lubricant composition consisting essentially of about to 99 weightpercent of a mineral lubricating oil, about 0.3 to 5 weight percent ofbarium mahogany petroleum sulfonate, about 0.5 to 1.8 weight percent ofzinc dialkyl dithiophosphate containing about 3 to 18 carbon atoms inthe organic radicals and about 0.3 to 3.5 weight percent of alkyl phenylphosphate in which each alkyl chain present contains about 3 to 18carbon atoms, said composition having a viscosity index of at leastabout and a viscosity (SUS) at 100 F. of about 650 to 1000.

9. The composition of claim 8 wherein the sulfonate is carbonated.

10. The lubricant composition of claim 8 wherein the alkyl phenylphosphate is diamyl phenyl phosphate.

11. The lubricant composition of claim 8 wherein the composition has aviscosity index of at least about 95.

12. The lubricant composition of claim 8 wherein the alkyl phenylphosphate is diamyl phenyl phosphate and the composition has a viscosityindex of at least about References Cited in the file of this patentUNITED STATES PATENTS 2,340,331 Knutson et a1. Feb. 1, 1944 2,369,632Cook et al Feb. 13, 1945 2,418,422 Palmer Apr. 1, 1947 2,638,447 Otto eta1 May 12, 1953 2,698,835 Otto Ian. 4, 1955

1. A LUBRICANT COMPOSITION CONSISTING ESSENTIALLY OF ABOUT 75 TO 99WEIGHT PERCENT OF A MINERAL LUBRICATING OIL, ABOUT 0.3 TO 5 WEIGHTPERCENT OF A SULFONATE SELECTED FROM THE GROUP CONSISTING OF CALCIUMMAHOGANY PETROLEUM SULFONATES FAND BARIUM MAHOGANY PETROLEUM SULFONATES,ABOUT 0.5 TO 1.8 WEIGHT PERCENT OF ZINC DIALKYL DITHIOPHOSPHATECONTAINING ABOUT 3 TO 18 CARBON ATOMS IN THE ORGANIC RADICALS AND ABOUT0.3 TO 3.5 WEIGHT PERCENT OF ALKYL PHENYL PHOSPHATE IN WHICH EACH ALKYLCHAIN PRESENT CONTAINS ABOUT 3 TO 18 CARBON ATOMS, SAID COMPOSITIONHAVING A VISCOSITY INDEX OF AT LEAST ABOUT 85 AND A VISCOSITY (SUS) AT100*F. OF ABOUT 650 TO 1000.